This invention relates in general to spools and in particular to an improved spool for holding windings of optical fiber.
Optical fiber, or sometimes referred to as optical waveguide filament, is a small diameter fiber used to transmit information in the form of light pulses emitted from a laser. Optical fiber is generally made of composites of glass and plastic. The strands of optical fiber are very thin, delicate, and are relatively expensive to manufacture. Therefore, it is important to store the optical fiber so as to prevent damage thereto.
Optical fiber is typically wound onto spools for storage and for easy dispensing. The spools have a cylindrical body and a pair of annular side wall flanges extending radial outwardly from the ends of the cylindrical body. The optical fiber is wound around the cylindrical body between the pair of annular side wall flanges. The spools can also include a layer of foam material wrapped around the cylindrical body to further protect the optical fiber. Typically, the spools are made of plastic and can be formed by injection molding manufacturing processes. However, the shape of the spool makes it difficult to manufacture the spool as a single part by injection molding methods.
It is known to manufacture a spool assembly by fastening two spool halves together. Each spool half is formed by an injection molding manufacturing process. The spool halves can be identical parts such that each half includes a portion of the cylindrical body and an annular side wall flange extending radially outwardly from one of the ends of the cylindrical body. The spool halves have cooperating holes and pegs formed at the ends of the cylindrical bodies to guide the spool halves together in a co-axial orientation. The spool halves are fastened together by applying an adhesive to the open ends of the spool halves and then joining the spool halves together such that the adhesive is disposed between the spool halves. It is difficult to obtain very close tolerances since the layer of adhesive may set at a non-constant thickness between the two spool halves. An uneven thickness of the adhesive can misalign the spool halves so that the annular side wall flanges are not parallel to each other. Non-parallel annular side wall flanges can cause the optical fiber to be incorrectly wrapped around the cylindrical body. The width between the annular side wall flanges should also be accurate and constant so that different spool assemblies will have the same length of optical fiber wound around the cylindrical body.